Withstanding 20 Gs

Wada: Even before NV-U35 development, there was a need for mounting portable GPS devices on bicycles. We knew this because several third-party Nav-U brackets were already available. Still, many of these fasten the unit to bikes tightly with a large knob bolt, which makes adjusting the angle of the screen difficult.

Each bicycle has different handlebars and presents the screen at a different viewing angle. Making the screen adjustable independent of the arm would be the most flexible arrangement. That's why this time, we designed a genuine Sony bicycle cradle (NVA-BU2). The dedicated cradle enables one-touch adjustment of the viewing angle and discourages theft because you can detach it immediately.

We faced a formidable hurdle when developing the tilting and attachment mechanisms. Bicycle handlebars are constantly subjected to tremendous force. Before development, our team members in design, planning, engineering, and quality assurance brought in bicycles with impact sensors on the handlebars. Measurements revealed just how much force the handlebars are subjected to, especially on road bikes without suspension. On city streets, the force is about 20 G. The magnitude of this force was a bit shocking to us.

It would be hard to deal with in design. Our engineers struggled to reconcile two conflicting goals: keeping the unit easy to attach and remove while ensuring that vibrations would not shake it loose. Meanwhile, I was busy exploring how to prevent vibrations from interfering with safety and screen readability. Although it might look cool to mount the NV-U35 directly over handlebars, the screen would be jostled out of your line of sight to a greater degree. On the other hand, extending the unit on the cradle arm would magnify vibrations, sacrificing screen readability. It was a matter of striking the right balance between these two by finding the ideal arm length.

I tried prototype on a mountain bike, riding over a rocky river bed and down stairs. Members of the quality assurance team took road bikes out on city streets. It was a very "analog" approach, but we had to investigate any problems that might occur. Checking performance this way was unavoidable, because some things can't be predicted. Careful repeated field tests helped us distill what was needed in design and engineering.

If it's not easy to use, it's not Nav-U

Matsuda: I have contributed in Nav-U user interface design since the very first model. One thing has remained the same: our pursuit of navigation systems that even first-time users find easy to understand and operate. The NV-U35 certainly embodies this ideal.

Take the map screens, for example. On navigation systems, maps must be shown at the same time as buttons, the ETA, the current time, and other information. The more clearly this information is organized in separate areas, the easier it is to understand it all at a glance. We decided that information not displayed over the map should be shown against a black background. Providing greater contrast relative to the map enhances readability of information in both areas.

For convenient operation even on the diminutive 3.5-inch screen, we also refined the NV-U35 in other ways. A specific example is enlarging the software buttons as much as possible. The icons are helpful, too. Instead of being photorealistic, the icons resemble familiar traffic signs, which conveys the meaning instantly. Bicycle navigation systems are used in direct sunlight, so we were concerned that readability might be severely impaired. We ensured that even under these conditions, the information is clear from the shape. Part of fine-tuning the interface involved making button and function labels as large as possible and adopting highly legible fonts.

We took the opportunity to refine traditional gesture commands, used to zoom in or out or to find your way home by tracing shapes on the screen. It's a pressure-sensitive screen, so you can operate it while wearing gloves. This method of control-interacting with the screen as you're looking at it-promises to be more effective when you're riding a bicycle than when you're driving, because you may be constantly in motion.

The audio feedback, which may remind you of chirping or barking, is an interesting facet of the device. Beeps in a regular car navigation system might sound unpleasant when you're riding a bike or walking. They're carefully designed with high frequencies and tones resembling warning buzzers so that you can hear them above road noise, but they would sound annoying outside a car. In contrast, the beeps emitted by the NV-U35 are both audible and gentle on your ears, and they were appreciated in field tests during development.